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By Orlando Romig

PART I-PREPARATION OP METALLIC SINGLE CRYSTALS WITH ESPECIAL REFERENCE TO SINGLE CRYSTALS OP ZINC? As metals and alloys are composed, of, an aggregate of allotriomorphic crystals or grains, each possessing an individual orientation, the physical characteristics of a metal or an alloy are closely related to the properties of the individual crystals. The preparation and study of single metallic crystals are, therefore, matters of considerable importance. The advent of the X-ray spectrograph as a valuable metallurgical tool has magnified the importance of this subject, because the interpretation of some X-ray spectrographs is difficult unless single crystals are used in these studies. PREVIOUS WORK The first paper, as far as the writer knows, on the behavior or preparation of single crystals of metals is by Baker.1 He describes the behavior of extruded wires of sodium and potassium. These wires, when pulled in tension, instead of I showing the usual conical fracture common to most metals, had a chisel-shaped fracture when they were broken. I and II, Fig. 1, have a similar fracture. Baker checked his results by preparing single crystal wires from molten sodium and potassium and observing their properties. He prepared the wires by filling glass tubes, under oil, with the molten metal. The surfaces of the strained wires showed slip bands of remarkable clearness of which photographs are shown in his paper. He concluded that these wires were single crystals and "that the portions of the metal brought into play are cubes. Such cubes, when placed so that a plane through 'two opposite edges was parallel to the axis of the wire, would allow of lateral contraction by faces gliding over one another in one direction only and not in the direction at right angles."

Jan 1, 1927

By W. J. Schuster

Safety in coal mines depends largely upon adequate training of the foreman. Although management must provide modern and safe equipment and at all times keep mines in first class condition from a safety viewpoint, final results will be determined by the quality of supervision. HANNA COAL CO., Division of Pittsburgh Consolidation Coal Co., operates three large underground mines in eastern Ohio. The section of Pittsburgh No. 8 coal seam in which these mines are located varies in thickness from 52 to 64 in. It is immediately overlain by a stratum of shaly material 12 to 15 in. thick locally known as draw slate, which is structurally very weak and which disintegrates rapidly upon exposure to atmosphere. Immediately above the draw slate as it is normally found is a band of extremely high ash material 6 to 12 in. thick known as roof coal or rooster coal, and above this is a stratum of conglomerate material varying from 4 to 10 ft in depth. Overlying the conglomerate is a relatively thick stratum of limestone, the first stable material above the Pittsburgh coal seam in eastern Ohio. With the method of full-seam mining that has been adopted, draw slate is shot down, loaded with the coal, and removed in the preparation plants. The roof coal then becomes the permanent roof. The major problem in mining the No. 8 seam in eastern Ohio is control of the roof. Since the strata above the draw slate contains no material with a structure firm enough to provide self-support, the roof begins to sag in a relatively short time after the coal and draw slate have been removed. The problem thus becomes one of getting temporary safety posts under this roof as quickly as possible to prevent a break or separation from occurring either in the roof coal or in the conglomerate above it. Haulage System The Pittsburgh No. 8 seam in eastern Ohio is relatively level, with only minor local dips. Throughout the Hanna Coal Co. mines, entries are generally 12 ft wide. Rooms are driven on a 60" angle on 30-ft centers and are 22 ft wide. No attempt is made to extract the 8-ft pillars between. The entire length of main line haulage is gunited in one mine, and a major portion in another. Two of the mines have single-track main haulage roads with passways. The third, a new mine, is double-tracked, and the roof is supported by steel crossbars, 60 lb or heavier, spaced on 4-ft centers and lagged. In recent years timbering on main line and secondary haulage roads has been accomplished by one of two methods: 1—crossbars are supported on a small section of post set in a hitch hole in the rib, or 2—or a hole is drilled in the rib about 12 in. below the roof, of sufficient depth to fasten securely a short length of 40-lb rail, the bottom of the rail facing the roof, on which a short post is set directly under the crossbar. At present the hitch-hole timbering method is favored. At two of the mines the main line haulage locomotives are 26-ton, 8-wheel units. These locomotives are of the axleless type, each wheel being individually mounted on the frame. The motorman's compartment is encircled by 3-in. armor plate for the protection of the occupants. At the third underground mine conventional 15-ton locomotives are being used. However, these locomotives have been completely rebuilt in the company's shops. Equipment has been streamlined and quarters have been provided for two people, who are protected by heavy steel plate in much the same way described above. This modernization program has been completed on all secondary haulage locomotives at the three mines, and the company is well on the way to similar equipment of the 6-ton section locomotives. The following additional features have been included in their modernization: 1—additional support for the motors to prevent their falling to the middle of the track and derailing the locomotives should a break occur in the suspension bar support; 2—installation of additional bracing to prevent brake rigging from becoming displaced and causing derailments; 3—enclosure of all electric wiring in conduit or raceway; 4—provision of an enclosed compartment for the storage of re-railers, jacks, and other equipment, so that they need not be carried on the outside of the motor; and 5—redesign of the end of the locomotive opposite the operator's compartment to prevent anyone's mounting from that direction. It is interesting to note that some

Jan 1, 1955

By J. D. Anthony

The Australian continent possesses significant reserves of a wide range of minerals, including bauxite, coal, copper, diamonds, gold, iron ore, lead, manganese, mineral sands, nickel, phosphate, silver, tin, uranium, and zinc. Australia's identified economic resources of many minerals are very large as indicated in Table 1. A sophisticated and highly experienced mineral industry is now an established feature of the Australian economy and Australia is the world's largest exporter of iron ore, alumina, mineral sands and refined lead and amongst the leading suppliers of many other commodities such as coal, lead and zinc ores/concentrates, nickel, refined zinc, tungsten concentrates and bauxite. The industry exports 70% of its production. This is reflected in the value of Australian mineral exports which have grown from about $200m in 1960/61, comprising 10% of total export receipts, to about $1265m or 29% of export income in 1970/71 to around $7061 representing 37% of Australia's total export income in 1980/81. Details of the more significant minerals are as follows: Japan (42.1%) USA (11.3%) ASEAN (6.3%) UK (5.9%) F.R. Germany (3.8%) Republic of Korea (3.4%) New Zealand (2.6%) Also see Table 2. AUSTRALIA'S MINERAL RESOURCES POLICIES Federal and State Governments' Responsibilities Australia has a federal system of government comprising six States, a self-governing Territory and a Federal Government. Under the Australian federal system the Constitution sets down the powers of the Federal Government. All powers not assigned to the Federal Government in the Australian Constitution reside automatically with the States. Certain of these broad powers result in the Federal Government having a significant influence on resources development. For example, in being responsible for economic management, the Federal Government's fiscal and monetary policies have an important effect on industry as well as on State finances. In particular, the taxation regime employed by the Federal Government is of direct importance to decision-makers in the resources industry. The Federal Government is responsible also under the Constitution for external trade matters; and international trade and commodity matters are increasingly important in Australia's international relationships. Foreign investment is another area where the Federal Government has a role to ensure that national interests are protected. This foreign investment power flows from the Federal Government's control of foreign exchange movements into and out of Australia. However, before enlarging on these and others of the Federal Government's powers and policies, it should be emphasized that the State governments, by virtue of their wide powers to regulate matters within their own boundaries, are more directly involved in the day-to-day administration and regulation of mining operations. For instance, the powers of the State governments include the responsibility-for the granting of exploration rights and mining leases, the approval of mining operations and the levying of royalties and other like charges. Administrative arrangements covering the granting of minerals and petroleum exploration and development titles vary from State to State. Before development rights are granted, State governments consider environment protection and rehabilitation aspects of development proposals. The provision of infrastructure within State borders is a matter primarily of State government responsibility. It is usual practice in Australia for State governments to construct and operate infrastructure services such. as railways, ports and electricity generation and transmission. The States may also provide certain public services such as electricity. and water, port and loading facilities, communications, health and education services which form part of the infrastructure of mining operations. In remote areas the mining companies themselves usually are expected to provide much of this infrastructure. However, the Federal Government is primarily responsible in some fields, such as telecommunications and parts of the railways network. State governments carry out preliminary exploration and geological mapping and some are directly involved in the mining of coal for power generation. The Federal Government's responsibilities in addition to economic management, taxation, international relations, foreign capital and investment, include regulation of exports, environmental matters and matters affecting the Aboriginals of the Northern Territory. FEDERAL GOVERNMENT POLICIES The continued sound development of the minerals and energy resources sector is regarded by the Federal Government as being of very great importance. However, the Government does not seek to participate directly in resource developments. It sees its role rather as that of establishing a sound economic and policy climate in which private companies can identify opportunities, seek out customers and marshall the necessary capital for the development of resource projects.

Jan 1, 1982

By K. E. Nelson

The effect of thorium and zinc variations on the strength and 100-hr creep characteristics of Mg-Th-Zn-Zr alloys was investigated. Optimum resistance to creep at 650° and 700°F are attainable within a certain range of thorium and zinc contents. This range does not conform to that which develops maximum tensile properties. RAPID advances have been made during the last few years in the development of magnesium alloys for elevated temperature applications demanding high resistance to creep. The beneficial effect of rare-earth metals on the creep resistance of magnesium alloys has been emphasized by a number of publications1-13 and such alloys are now in commercial production. The use of thorium as an alloying ingredient in magnesium was mentioned by McDonald and also in two Alien Property Custodian patent applications.10,17 The initial observation of Sauerwald that thorium contributes still higher creep resistance to magnesium than is attainable with rare-earth metals has recently been substantiated.'" " In fact, it has been demonstrated that the useful temperature range of magnesium alloys is appreciably extended by the use of thorium. In all cases, it was observed that zirconium must be included in the alloys in order to render them fine grained and more readily castable. Several recent publications:2-27 indicate that a still further improvement in creep resistance and a further extension of the useful temperature range can be realized by the addition of zinc to alloys. The primary purpose of this paper is to present the results of a comprehensive study of the effect of zinc on the strength and creep characteristics of Mg-Th-Zr alloys. Compositions covering the range of thorium content from M to 6 pct and zinc content from 0 to 5 pct have been investigated. The creep characteristics at 650" and 700°F reported in this paper are based on results of tests of 100-hr duration. It is appreciated that creep tests of 100-hr duration might not yield adequate data for design purposes for parts with much longer expected life. However, for the purposes of the present discussion, it is felt that the combination of stresses and temperatures used in the 100-hr creep tests have yielded a clear representation of the compositional variation of creep resistance at the temperatures investigated. Creep tests of 1000-hr duration are now in progress on a few of the most promising alloys. Preparation and Testing of Alloys The alloys studied in this intensive investigation were prepared in 25 lb capacity mild steel crucibles. The thorium, zinc, and zirconium were alloyed and poured as described in earlier publications The thorium was introduced into the melt in the form of a Mg-Th hardener," the zinc added in the metallic form, and the zirconium alloyed in the form of the commercial hardener containing magnesium and 30 to 50 pct Zr.10, 26 Fluxing practices for melting and refining were the same as for magnesium-rare-earth metal-zirconium alloys. The melts were sampled for analytical determinations and poured into separately cast 1/2 in. diameter standard tensile bars. The test bars were given a precipitation treatment of 16 hr at 600°F in laboratory furnaces. It has been shown by other tests that a high temperature solution treatment followed by an aging treatment is unnecessary for the development of optimum properties in Mg-Th-Zn-Zr alloys. The selection of 600°F as the aging temperature was based on an attempt to achieve metallurgical stability without coalescence of the undissolved phases and the attendant loss in strength. The thorium, zinc, and zirconium contents of each melt were determined chemically. The zirconium contents are reported in two parts, "soluble" and "insoluble," referring, respectively, to the portions present in the alloy which are soluble and insoluble in dilute HCl acid. Distinction is being made between these two components of the zirconium content in the alloys because it has been found that only that portion of the zirconium content which is soluble in dilute inorganic acids affects the structure and properties of the alloys. The usual impurities consisting of copper, iron, manganese, and nickel were determined spectroscopically. The analysis for each melt is listed in Table I. A description of the methods of tension and creep testing has been detailed in earlier papers. The tests were performed with the cast skin re-

Jan 1, 1954

By F. L. Holderreed

A choosy in what they would smelt. The furnace charge had to be coarse, and it had to be rich. They discarded fines in excess of about 1/10 the total weight. They wanted 10% copper content and fussed about anything with as low as 5%. They concentrated the copper content of the charge as much as they could by prior selection. They roasted off enough sulfur to further enrich the copper content of the succeeding fall of matte (a melt of cuprous and ferrous sulfides or Cu2S.FeS). Then they desulfurized the iron and fluxed it by carefully adding silica (quartz, not silicates) for a slag of lower density than the cuprous sulfide (Cu2S or white metal). After skimming off the slag, they further desulfurized the white metal by blowing the molten bath with compressed air. The result was blister copper. Yesterday Their techniques and furnaces? Some experimented with mechanically rabbled roasters, but their standard roasting practice was burning coarse sulfide ore in 250-ton heaps. These heaps, approximately 24 x 24 x 6 ft, were burned for about 75 days down to 6-10% sulfur. The turnaround time for a given roasting position was 100 days. Assuming the base was a hearth, the calculated rate of treatment was on the order of 0.004 tpd per sq ft.

Jan 1, 1971

By DR. RICHARD RATHBUN

(Washington Meeting, May, 1965.) THE remarks of Dr. Rathbun in his address of welcome render it unnecessary that I dwell either upon the history or aims of the National Museum, and enable me to proceed at once with a brief descriptive outline of the Department for which I am responsible, and this with particular reference to that division devoted to applied geology. The amount of geological material brought together prior to 1876, under the various Congressional acts quoted, was, though valuable, comparatively small. It consisted mainly of the collections made by Professor J. D. Dana and his assistants during the Wilkes Exploring Expedition; by the various geologists accompanying the surveys of the Pacific railroads in 1854-55; the Surveys West of the 100th Meridian under the direction of the Engineering Corps of the Army; the United States geological surveys under direction of Dr. F. V. Hayden ; and the various Land Office surveys. Prior to 1873 there were no paid assistants to care for these collections. They were studied, if studied at all, by " collabrators," so-called, several of whom had offices and even sleeping apartments in the Smithsonian Institution. In the list of these collaborators are found such names as Conrad, Cope, Gabb, Leidy, Lesquereux, Meek, and Newberry. The building now occupied by the National Museum was designed primarily to make room for the great mass of material secured in 1876 at the close of the Centennial Exposition in Philadelphia. As completed in 1880, it afforded opportunity for expansion and incidental organization on much more practical basis than had previously existed. This found expression in the creation of numerous departments with salaried officials to take charge of the various collections. With the appointment of Dr. George W. Hawes to the position of Curator of Geology and Mineralogy, in 1881, and Dr.

Jul 1, 1905

By Mark L. Requa

(San Francisco fleeting, October, 1911.) DURING the past two years California has developed a new and important oil-field : I refer to Midway. This field produced the famous Lake View gusher, which is credited with a total production in excess of 8,000,000 barrels. Fortunately for the oil industry of the State, this well is now a thing of the past, and nothing save a great crater-like opening marks its location. The pipe is entirely worn away and gone ; and it is a matter of serious doubt if there can be anything done that will cause the well to produce again. Fortunately, also, there have been no, other wells in that field or elsewhere throughout the State that in any way compared with the Lake View. Midway is noted for large wells, of from 500 to 2,000 barrels production; but the decline is rapid, and a few months serve to bring the output down to a few hundred barrels. In the oil-territory heretofore blocked out as proved and probable, there have been, during the year, many changes. Some areas which were expected to be fairly productive have apparently failed; others, more strictly "wild-cat," have come in; while in some of the older fields there are properties which are beginning to show evident signs of exhaustion. The total area of proved territory will therefore probably suffer but small increase, when balances are struck off. The increase of new area has come from extensions of the Midway field, the development of a field in Lost Hills and Belridge, and extensions of the Fullerton-Whittier field in southern California. In these later developments, down to date, the fresh area absolutely proved is not much in excess of 3,000 acres. Recent developments in Coalinga indicate the possible extension of that field to the south, but at great depth. Coalinga is still the most northerly field of any consequence in the State. The Kettleman Hills have hitherto brought in nothing, although a

Apr 1, 1912

By H. W. Knott, M. H. Mueller

The crystal structures of Ti2Cu, Ti2Ni, Ti4Ni2O, and Ti4Cu20 have been determined using powder specimens examined by X-ray and neutron diffraction. Lattice constants have been determined for all four phases using X-ray powder diffraction films. Atom positional parameters of all four phases have been determined from observed neutron intensities. X-ray diffraction calculated intensity data have been presented also for the phase Ti2Cu to point out the particular suitability of neutron diffraction in this case. Interatomic distances have been determined using the positional parameters obtained from neutron diffraction. ALTHOUGH some investigations of the crystal structures have been made of these four compounds previously,'-13 it was the purpose of the present investigation to expand the previous work in order to locate the various atoms, determine their coordinates, and to confirm or to correct some of the previous work. It was convenient to group these four compounds together since they are related chemicallv and/or structurally. The compound Ti2Cu is tetragonil; and Ti2Ni, Ti4Ni2O, and Ti4CU2O are all large fees of the same space group. Ti2Cu has been previously reported as a fee phase by Laves and Wallbaum;1 and Rostoker2 which was possibly the oxide phase, Ti4Cu20. Joukainen, Grant, and Floe;3 and Trzebiatowski, Berak, and Ramotow-ski4 have also reported a phase of this composition. karlsson5 has reported a small fct phase of the composition Ti3Cu which may be the presently discussed Ti2Cu phase. More recently Ence and Margolin6 have reported a small fct phase for Ti2Cu and the present authors7 together with Nevitt8 have briefly reported it to be a bet related to the fct with a co three times the length of the co of the fct and have also reported that this phase has a very limited composition. Further refinements will be reported which have varied some of the parameters of this bct structure slightly. Ti2Ni has been reported as a fee phase by Laves and wallbaum;1 Duwez and taylor;9 Rostoker;2 Poole and Hume-Rothery;10 and Yurko, Barton, and parr.11 In a later paper Yurko, Barton, and parr12 have given the complete structure of this phase based on an X-ray diffraction study which was independently confirmed with neutron diffraction by Mueller and knott.7 Additional crystal structure information will be given. Ti4Ti2O, Ti4Cu2O, and a number of other compounds including Ti4Fe2O have been reported as fcc phases by Rostoker,2 and more recently Nevitt13 has confirmed the Ti4Ti2O phase. Rostoker,2 however has reported diffraction lines for Ti4Fe2O which do not have all odd or all even indices. These lines, therefore, cannot be observed if this compound has a fee structure. This same error has crept into the diffraction results reported for TiNi2O and Ti4Cu20 in the ASTM powder data which has been credited from Rostoker's data. Complete crystal structures of these two phases will be presented. Although all four of these structures have large unit cells and hence do not lend themselves for completely resolved neutron powder patterns, a sufficient number of individual reflections was observed for solving the structure. They also serve as good examples of some of the advantages to be gained by using both neutron and X-ray diffraction techniques. EXPERIMENTAL PROCEDURE All of the alloys were prepared by arc melting. The starting metals had the following purity: Cu 99.999 pct, Ni 99.83 pct, and Ti 99.92 pct. Oxygen was introduced into the two oxide phases as chemically pure TiO2, with the remainder of the titanium coming from the above mentioned metal. All of the sample buttons were annealed in evacuated Vycor tubes, the two binary phases for 5 days at 700°C and the two oxide phases for 3 days at 900°C. Oxygen analyses were performed on all four phases by two independent laboratories with the following amounts of oxygen present in atomic percent; Ti2Cu-0.06, Ti2Ni-1.03, Ti4Ni2O-13.95, and Ti4Cu20-13.87. The stoichiometric amount for the oxide phases is 14.29 at. pct. Since all of the samples were very brittle they were easily reduced to a powder for diffraction measurements. The lattice constants given in Table I were determined for the four compounds from X-ray diffraction patterns of powder samples exposed to filtered copper radiation using a 114.59 mm diam Debye-Scherrer type camera using the Straumanis loading. None of the patterns showed a detectable amount of a second phase. The lattice constants were obtained from an IBM 704 computer program employing a least squares treatment with systematic correction terms as previously reported.14

Jan 1, 1963

By William B. Millar

IN ONTARIO development of the gold mines is being rapidly pushed, while the intensity of the search for new mines has probably not been equaled at any time in the past. Even to outline the results of recent prospecting activity in Ontario would be a big undertaking, but it would be timely and, I hope, interesting to Institute members to review some generalities regarding the work of the prospector and then to discuss in some detail the growth of Ontario's most promising prospect area, the Swayze district, where serious mining operations are already under way. Probably no one writing about prospectors and pros¬pecting can resist hoping that his article will not reach the eyes of a certain portion of the uninformed general public and cause a further influx of "prospective prospectors" into any given area. It is somewhat mystifying how so many people reach the conclusion that prospecting is in

Jan 1, 1933

By R. Lagneborg, R. Gullberg

An X-ray method for determinig volume fractions of phases in textured materials has been developed. The method involves measurements of the integrated intensities of reflections of each phase for one single orientation of the sample. The method was checked by evaluating the phase contents in samples from two stainless Cr-Ni steels containing austenite and ferrite in known amounts. In the present case measurements of about five reflections from each phase were required. The agreement between calculated and known volume fractions was found to be very close. AN X-ray diffraction method is often employed for determining the amounts of two or more phases in a material. The details of the method have been described at several instances.'" In short, the method is based upon the fact that the integrated intensity of a reflection is directly proportional to the volume fraction of the phase considered. In principle, the method only requires the measurement of the intensity of one reflection for each phase. The most severe shortcoming with this method is that it disregards influences from preferred orientation in the material. In a diffractometer, where this type of analysis is most conveniently carried out, the geometry is such that the diffracting planes for a specific Bragg peak are all parallel to the surface of the specimen. This implies that it must be required that the occurrence of the diffracting planes parallel to the specimen surface must be as frequent as for any arbitrarily oriented physical plane of the sample. This requirement will generally only be fulfilled for a material free of texture. Since all materials in reality always exhibit a preferred orientation to some extent. the deficiency of the method is quite serious. In cold-deformed material the texture is appreciable, but also annealed material will in many cases display a considerable texture. The problem of quantitative phase analysis in textured material is one of obtaining the integrated intensity averaged over all orientations of the specimen with respect to the X-ray beam. Lopata and ~ula~ have shown that this can be accomplished by integration of intensities over the whole pole figure, or by random rotation of the specimen in the X-ray beam, or by a combination of both. Hence, in this method the average integrated intensity for a specific reflection is obtained by directly determining the intensity for a sufficient number of physical orientations of the sample. However, since an excess of diffracting planes in a certain surface plane necessarily must be accompanied by a deficiency of another type of diffracting plane, it appears to be possible to obtain the correct average intensity for a specific diffracting plane by performing an appropriate averaging of intensities belonging to a large number of diffraction planes of different hkl when all intensities have been produced from one single orientation of the specimen surface. In the present work such a method has been attempted and tested experimentally for two stainless Cr-Ni steels containing austenite and ferrite. 1) THEORY The expression for the integrated intensity of a Bragg reflection diffracted from a phase in a polycrys-talline sample in a diffractometer is: where C is a constant only dependent on the incident X-ray power and the diffractometer geometry, v the volume of the unit cell, F the structure factor, m multiplicity of the diffracting plane, L Lorentz factor, P polarization factor, e-2 temperature factor, p average linear absorption coefficient of the irradiated vO1umej and V volume fraction of the phase 'Onsidered. Hence, the factor R in the abbreviated form of Eq. [I] can be calculated and depends only on 0 and the diffracting plane {hkl}. For an alloy containing two phases, a and y, we can write

Jan 1, 1967

By M. J. Hordon

Measurements of the 103 yield stress of ordered and disordered poly crystalline Cu ,Au were related to the ordered antiphase domain size determined by resistivity measurements. For undeformed material, a yield stress maximum wa obtained at a critical domain diameter of about 40A. Plastic deformation resulted in a marked increase in the yield stress and electrical resistivity of the ordered alloy compared to the disordered, the strain hardening rate increasing regularly with initial antiphase domain size. Order hardening was accompanied by a sharp reduction in size of the initially large domains. It has been observed that the yield stress of ordered and partially ordered Cu3Au alloy varies sensitively with antiphase domain size aid degree of order.ly2 In addition, ordering of the lattice leads to a marked increase in the strain hardening rate (order hardening) as compared to the rate for the disordered alloy. In the present investigation, changes in the electrical resistivity and yield stress of ordered polycrystalline Cudu with varying initial domain diameters were measured after tensile plastic deformation in order to examine the effect of cold work on the antiphase domain size. EXPERIMENTAL PROCEDURE Au-Cu alloy of 99.99 pct purity analyzing 50.85 wt pct Au-balance copper was obtained from the Handy-Harmon Co., N. Y., in the form of 0.061 in. diam drawn wire. Wire specimens 3 in. in length were given the following annealing treatment in nitrogen: 500" for 72 hr, 820" for 15 hr, and 450" for 5 hr, followed by a water quench. The annealing sequence resulted in a completely disordered structure with a grain size of about 0.2 mm. The disordered specimens were then reannealed at 360' in nitrogen for periods varying from 10 min to 150 hr followed by quenching to produce ordered structures with varying domain sizes. The degree of ordering and variation of domain size was followed by electrical resistivity measurements made at room temperature using a low resistance precision Kelvin double bridge apparatus. The specimen resistance was determined over a length of 4.0 cm between two brass knife-edge contacts while the specimen was immersed in an oil bath to minimize temperature variations. In addition, the current flow in the circuit was minimized by a current pulse technique in balancing the bridge in order to avoid heating the specimen. Using a sensitive galvanometer to detect the bridge null, the accuracy of the resistance measurement Wire specimens were plastically strained in tension with an Instron tensile unit at strain rates in the range 5 x 10"5 sec-' to 2 x 10"4 sec-'. Stress and extension data were fed into the Instron chart drive amplifier to obtain the actual stress-elongation curve from which the yield stress at 10"3 strain was determined. The maximum resolution of the apparatus was approximately 50 psi stress and 3 x 104 strain. At various plastic strain levels, deformation was interrupted and the electrical resistivity determined after removing the stress. RESULTS AND DISCUSSION 1) Yield Strength of Ordered Cudu. In order to determine the effect of the ordered antiphase domains on the initial yield stress, specimens were prepared with varying domain sizes ranging from zero for 5 completely disordered structure to about lo5A for a completely ordered structure by suitable annealing treatment. Domain sizes were estimated by comparing room temperature electrical resistivity data with the original data of Jones and sykes3 as modified by rdle.' In agreement with previous work, the resistivity varied sensitively with domain diameter and degree of order, decreasing from approximately 11.6 x l0- ohm-cm for the disordered structure to about 5.9 x l0- ohm-cm for ordered domains above 10"3 cm in diameter. Fig. 1 shows the change of the 103 yield stress with ordered domain size. It is evident that the maximum

Jan 1, 1963

By R. S. Shoemaker, F. W. McQuiston

CARLIN GOLD MINING COMPANY 1974 Operating Data to October MINE LOCATION: 40 miles from Elko, Nevada ORE DESCRIPTION: Gold with minor amounts of mercury occurring in siltstone and carboniferous limey shales. TYPE OF MINE: Open pit ORE HAULAGE TO MILL: By trucks up to a distance of 12 mi1es MILLING CAPACITY: 2500 tons per day ORE GRADE: 0.20 oz per ton oxide ore 0.25 oz per ton carbon type ore PRODUCTS: Gold bullion 993 fineness, by product quicksilver RECOVERIES: Oxide ore 887'0 Carbon ore 83% POWER FOR GRINDING: 7 Kwh/T POWER, other than grinding: 14 Kwh/T WATER SUPPLY: Pumped from wells 2- 112 miles through 13,000 ft of 8" buried pipe 6 ft underground. Consumption 0.60 tons of new water per ton of mill feed. TAILINGS: By 10" woodstave pipe a distance of 2500 ft to mine waste filled dam. RUNNING TIME: 10 ft x 10 ft mill on oxide ore, 98% 7 ft x 8 ft mill on carbon ore, 937'0 Principal causes of lost time, power outages and problems of feeding gaseous chlorine to carbon ore agitators. LABOR, TONSIMAN SHIFT: See detailed data sheet ILL BUILDING DESCRIPTION: Framed structural steel with sandwich type walls of marine plywood, then packaged pre - fabricated insulation and outer sheeting of galvanized corrugated steel.

Jan 1, 1975

By L. Leibowitz, M. G. Chasanov, L. W. Mishler

A drop calorimeter system is described for use in measuring enthalpies to 3600°K. Data are presented for tungsten between 2800" and 3600°K. The enthalpy of tungsten in cal per mole between 2000° and 3600°K can be represented by the equation HºT- Hº298 = - 1.7622 X 103 + 5.7772T + 8.9861 where T is in degrees Kelvin. A tabulation of com -puted values is presented for heat capacity, entropy, and free energy function. A drop calorimeter has been constructed to carry out enthalpy measurements at temperatures to 3600°K. Samples are heated by induction1 and dropped into a commercial adiabatic calorimeter, modified for this purpose. The experimental temperature is limited by the melting point of container materials and compatibility of the container and its contents. Several high-temperature drop calorimeters have been described in the literature1-5 but none has been used at temperatures as high as those in the present work; our measurements of the enthalpy of tungsten range from 2800" to 3600°K. DESCRIPTION OF EQUIPMENT An overall schematic view of the equipment is shown in Fig. 1. Power for the induction coil is supplied by a 25-kw 250 kHz Ther-Monic generator coupled to an iron core RF transformer. The Sample capsule is suspended in the work coil by 10-mil diam tungsten wires which are wrapped around a horizontal 5-mil diam tungsten wire. The horizontal suspension wire is clamped between two massive copper electrodes which are fixed in an x-y motion device that allows adjustment of the position of the heated capsule from outside the vacuum chamber. The copper electrodes are connected by flexible copper straps to a 1250-joule (5 kv, 100 pfarad) condenser bank. When it is desired to release the capsule, the condensers are discharged through the horizontal suspension wire causing it to vaporize rapidly. Very reliable and precise release of the capsule is achieved in this manner. Experiments have shown that no heat correction is required for this discharge energy. As part of the temperature measuring system, two prism holders have been incorporated in the apparatus. The upper prism holder is in the main vacuum chamber itself, whereas the lower one is in a side arm attached to the drop tube below the gate valve. The upper prism is mounted on a rotary vacuum feed-through, and may be moved under a protective shield when not in use. This prevents deposition of vapors on the prism surfaces when temperature measurements are not being made. Similarly, the lower prism is mounted on a push-pull vacuum feed-through, and when not in use may be pulled into its side tube. The prism mountings are fitted with guides and stops so that they may be moved precisely into the desired position. The aim throughout is to minimize the time the prisms are exposed to vapors from the hot samples. At the high temperatures reported in this paper, only the lower prism was used. The upper prism holder in these cases was fitted with an additional radiation shield. By using a prism and viewport, the lower surface of the samples can be observed by an optical pyrometer. The measurements discussed in this paper were obtained with a Leeds and Northrup 8622-C-S series manual pyrometer which is estimated to be accurate to 0.5 pct. Pyrometer calibrations and prism and window corrections were carried out in the conventional manner6 using tungsten strip lamps calibrated by the National Physical Laboratory, Teddington, England. Prism corrections were rechecked after each use. All work to date has been done in vacuum, and no measurable change has been observed in the prism correction below -2300°K for the upper prism and below -2800°K for the lower one. The total time of exposure of the prisms is about 50 sec per run. At high temperature, the final temperature reading is corrected by using the final A value for the prism; see Ref. 6 for details of this procedure. The calorimeter is a modified Parr Instrument Co. (Moline, lll.), Series 1230 adiabatic calorimeter with automatic jacket control. Other authors5 have used a similar calorimeter with good results. The calorimeter jacket cover and calorimeter cover are attached to the drop tube which contains a radiation shield. This shield is a gold-plated copper disc which can be operated manually from outside the calorimeter. The receiver is attached below the radiation shield and is lined with tungsten. In a typical experiment, the calorimeter and its jacket water temperatures were adjusted to 0.000°K temperature difference. The sample was allowed to equilibrate in the furnace at the desired temperature for about 20 min. The initial calorimeter temperature was then recorded, the sample dropped, and appropriate shutters closed. After about 3 min, the drop tube and receiver were filled with helium to 60 torr. The final calorimeter temperature was recorded after it had remained constant over a 5-min period. The equilibration time in the calorimeter was about 25 min. Thermistor probes are used to operate a hot and cold water supply system to maintain the jacket temperature equal to the calorimeter temperature. For actual measurements of the calorimeter temperatures, a quartz thermometer was used (Hewlett Packard Dymec Thermometer, Model #2801A). This thermome-

Jan 1, 1970

By Arnold Hoffman

A RESPONSIBLE steel executive recently declared that scrap shortages, despite fantastic prices reaching up to $50 per ton, are responsible for the loss of 140,000 tons of steel a month and that in March 1947 alone 25 more steel furnaces could have been operating were it not for scrap scarcities. His answer to this serious situation was to ask for a speedier flow of scrap and also abolition of Government control over pig iron distribution. It would be more logical, perhaps, if an answer to this growing problem of scrap deficiency were sought within the steel industry itself. As long ago as 1933, L. B. Lindemuth, a consulting steel metallurgist, warned the steel industry that a shortage of scrap was inevitable and that beyond 1938, adequate supplies for open-hearth furnaces could not be expected. The outbreak of war, with consequent phenomenal demands on the industry, accelerated production of steel and further worsened the scrap situation. Today we are suffering from a condition which could have been prevented had the industry been more far-seeing and provided for an inevitable contingency. However, better late than never, and measures can now be taken to alleviate permanently scrap shortages in the future. This can be done by greater utilization of heavy sinter which experience proved is an excellent substitute for scrao and lump ore.

Jan 1, 1947

By Bernard Kopelman, C. C. Gregg

THE reduction of tungstic oxide to tungsten metal powder by hydrogen is a process by which one might expect the resultant metal powder to be porous. In- [ ] deed, sponge iron, prepared by reduction of the oxide in a reducing gas, is generally accepted as quite porous, with pores large enough to be seen readily under the optical microscope at relatively low magnifications. However, any pores that may exist in tungsten metal powder are not resolved by the optical microscope, and apparently, not even by the electron microscope. Fig I shows commercial tungsten powder magnified at 10,000X by the electron microscope,1 both etched and unetched. In an earlier paper by one of the authors,2 the existence of pores in tungsten powder [ ] was required to explain adequately the particle size changes occurring during the reduction of tungstic oxide. The inability to detect these pores under the electron microscope at 10,000 X implies that these pores are of a size of 100 A units or less. (This in itself is by no means proof that pores above 100 A would not exist, since polishing effects on the specimen might smear up holes of such small magnitude). If, then, these pores are less than 100 A, and of the order of molecular size, then the density of the metal powder should be

Jan 1, 1948

By H. B. Muller

Single stage autogenous grinding of run-of-mine ore was selected by Broken Hill South Ltd., parent Company of Cobar Mines Pty. Ltd. for the concentrator to treat 60,000 tons per four weekly period of copper and complex copper-lead-zinc sulphide ores from the C.S.A. Mine at Cobar, Australia. Ore is mined by mechanised horizontal cut-and-fill stoping and is prepared for grinding by crushing under- ground in a 60 in. x 48 in. jaw-crusher set at 5 in. closed side setting. The ore is reduced to 80% minus 76 microns in two parallel sections each of one 22 ft. dim. x 7 ft. long autogenous grinding mill, powered by a 1,250 H.P. motor, operating in closed circuit with a single stage 20 in. dim. cyclone. Broken Hill South's original concept of the concentrator required the maximum use of reliable instrumentation, centralised control, and the minimum of manning. To achieve this objective the control room, housing the process recorders, alarms, closed circuit television monitors and all the control equipment, overlooks the grinding and flotation sections, and the whole plant is serviced by a public address system. The grinding units and associated equipment are located in the open and are serviced with the aid of a mobile crane and a mobile hydraulically-operated liner lifting device.

Jan 1, 1970

By W. Geo. Waring

THE growing need of better methods for the recovery of zinc and other elements from complex sulfide ores has suggested an inquiry respecting a possible group separation of the elements by the aid of volatilization at more or less elevated temperatures. It 'is evident that if the zinc content of such ores can be completely separated, for instance, as pure oxide, by a volatilization 'method, there should be no difficulty in recovering the other elements by smelting and refining. Zinc burning" as applied to zinkiferous ores has advanced but little in practice since the invention of the wetherill grate-furnace process in 1852, as may be seen by reference to papers on the subject.' In other words the thermochemical reaction employed in effecting the volatilization of the zinc is essentially one of reduction by means of carbon, whether the ores treated contain their zinc in an oxidized form, or as the sulfide. The zinc vapors, liberated from the ores at a temperature above that required for the reduction of ZnO by C (about ,1100° C.) or for the volatilization of ZnS per se, (about' 1300°-1400° C.) are subsequently burned to ZnO or to ZnO + SOz, by contact with' atmospheric ,oxygen in the upper or posterior parts of the furnace chamber, or in a so-called "combustion chamber" after leaving the .furnace proper.

Jan 1, 1925

By E. H. Citron

CLEANING fine coal in jigs is not new in Europe, where the feldspar jig is being used almost exclusively for this purpose. A feldspar jig operates with an artificial bed made up generally of feldspar or other hard rock material. Dimensions and specific gravity of this material must be of suitable values for good bedding qualities. For good efficiency, the size should range between 1x2 in. and 2x2x½ in. thick. The disadvantage of an artificial bed is that it is not mobile and must be replaced every so often with new material to obtain good cleavage characteristics. A semi-mobile bed has been developed to retain only a part of the feldspar on the sieve screen— the other part is drawn off with the refuse material, from which it is reclaimed and returned to the jig feed. Recirculating this feldspar rock offers definite advantages. However, in time it will lose its original shape because of wear, and new bed material must be added to the jig feed. The latest feldspar jigs arc generally air-pulsated, Baum-type jigs, although more than 70 pct of the feldspar jigs operating in Continental Europe are still of the piston type. These jigs are very popular in Europe, but they do require a great deal of time and attention. New Theory to Eliminate Artificial Bedding: At the preparation plants of Pittsburg & Midway Coal Mining Co. it has always been the contention that a small piston-type jig could be developed to clean fine 1/4x0-in. coal down to 28 to 60 mesh efficiently by obtaining and admitting bedding material from the present plant refuse circuit to the jig feed. This eliminates use of artificial bedding materials. The jig should incorporate these essential adjustable features as follows: Adjustable Sieve Screen A screen that can be raised and lowered to increase or decrease washing compartment depth. The sieve screen also can be set on an incline level, or decline. Adjustable Plunger Eccentric Length of stroke can be adjusted to increase or decrease pulsion and suction. Variable Plunger Speed Variable speed reducer for decreasing and increasing the number of strokes per minute. Water Distribution Adjustable baffle plate separating the plunger and sieve compartment so the water can be distributed uniformly over the entire sieve screen area. Refuse Ejector Special unique rubber-type refuse ejector gate operated by air and electrically controlled (as a conventional jig). Automatic Control Conventional float that measures the specific gravity of the coal-water refuse medium in the jig is of the submerged type. The float is mounted on a vertical stem held in position by two parallel arms. A movable weight regulates the effective specific gravity of the float. The float stem can be raised and lowered, having a graduated scale to indicate the depth of bed for the setting of the float. Hutch Drawoff Hutch material is drawn from the cell compartment to the elevator compartment by gravity. The first one-cell experimental jig incorporating all these features was built in January 1955 by Ore

Jan 1, 1959

By A. H. Daane, J. J. Hanak, F. H. Spedding

IN the study of the rare earths at the authors' laboratory, methods have been devised for preparing pure rare earths and many of their properties'- have been determined. Very little information is found in the literature on the properties of europium metal, which is the scarcest of the naturally occurring rare earths. Since we have recently prepared europium in appreciable quantities, we are in a position to describe the method of preparation and some of the properties of this metal. Metallic europium was first prepared by Klemm and Bommera who heated a mixture of potassium and EuC1, in vacuo, and obtained a mixture of europium metal and KC1. Trombe4 electrolyzed a molten salt bath containing NaC1, KC1 and EuC1, and collected the europium in a molten cadmium electrode as a cadmium alloy. The cadmium was subsequently removed by distillation but the properties of the residue indicate that pure europium was not obtained. McCoy attempted to prepare europium by distilling mercury from europium amalgam, but the stability of the Eu-Hg intermetallic compounds prevented a complete separation of the two elements. The preparation of very pure europium was suggested by previous work in this laboratory1,4 in which ytterbium and samarium were prepared by heating the respective sesquioxides with lanthanum metal turnings to 1450°C in vacuo and distilling ytterbium and samarium from the mixtures. Subsequently, small test experiments showed that europium also could be prepared by this method. A more detailed version of this method was used in the work described in this paper. Klemm and Bommer3 found by X-ray analysis that the metal had a body-centered cubic (bcc) structure with a lattice constant a, = 4.582 ± 0.00A (converted from kX units), with a bulk density of 5.30 g per cu cm. They found europium to be weakly ferromagnetic. Spedding, et al,7 found a,, to be 4.606 ± 0.001A. Barrett' showed that the bcc structure persists throughout the temperature range 5 to 3000K with a, at 5, 78, and 300°K being 4.551 ± 0.003, 4.551 ± 0.004 and 4.577 ± 0.001A, respectively. Trombe1 described europium as being iron gray, malleable, about as hard as neodymium and not attacked by cold water. He estimated the melting point to be between 1100 and 1200°C. Previous work in this laboratory indicated that the pure metal corrodes rapidly in air and reacts with cold

Jan 1, 1959

By M. Kaufman, A. E. Palty

The phase structure and aging characteristics of two nickel-base alloys, Inconel 718 and 702, were investigated. Wrought and cast Inconel 718 showed ArisCb as the major hardening phase, as well as ture was positively identified. Inconel 702 had Ni3Al as the major hardening phase, as well as Cr7C3-of the phase amounts with temperature was determined. 1 HE value of phase structure and aging rate information in the utilization of alloys has been well established. As part of a continuing program, the results obtained on two nickel-base alloys, hconel 718 and Inconel 702, are presented here. Inconel 718 is a relatively new alloy considered for application in both sheet and cast form. Its novelty lies in the use of high columbium tantalum levels in a Ni-Cr-Fe base. No previous work on this type of alloy has been reported in the literature. Inconel 702 is being used now as an oxidation-resistant sheet alloy. Occasional fabrication problems spurred work on its basic structural behavior. The composition of 702 is essentially nichrome plus aluminum and titanium for strengthening and added oxidation resistance. This puts it in the basic class of other nickel-base alloys which have already been studied. The two alloys will be treated separately. INCONEL 718 Phase Study Methods. The phases present after the various conditions investigated were determined by X-ray diffraction analysis of two different elec-trolytically extracted residues and microscopic examination. The extraction methods, using 10 pct HC1 in alcohol and 10 pct H3PO, in water and the X-ray technique have been described previously.' The effect of temperature on the phase behavior was studied on sheet material using the following heat treatments: 2250°F, 2 hr, ice brine quench 1300 100 hr, water quench 2250°F, 2 hr, ice brine quench 1400°, 100 hr, water quench 2250°F, 2 hr, ice brine quench 1500°F, 100 hr, water quench 2250o 2 hr, ice brine quench 1700°F, 48 hr, water quench 2250°F, 2 hr, ice brine quench 1850°, 24 hr, water quench 2250°, 2 hr, ice brine quench 2000°F, 6 hr, water quench The high solution temperature was an attempt to dissolve as many phases as possible without causing melting. Aging exposures were made longer than normal heat treating times in order to approach equilibrium conditions more closely. Cast material was examined only in the as-cast condition and with the normal heat treatment (1700°F, 1 hr, air cool 1325oF, 16 hr,air cool). Materials. The full phase study was performed on sheet specimens approximately 1/2 in. by 2 in. by 1/16 in. The cast pieces were cut from the gating system of a vacuum-cast test piece. An all weld-metal specimen was made by running many weld beads on the sheet using filler made from the sheared edges of the sheet. All external contamination was removed by belt-sanding followed by an electro-polishing treatment. The typical composition of wrought Inco 718 is as follows: The alloy is air-melted. Cast hco 718 may have higher molybdenum. Due to the expectation of finding a Ni-Cb phase (Ni, Cb) for which no X-ray diffraction pattern was available in the ASTM Index, a special 5 Ib heat to the stoichiometric composition of this intermetallic

Jan 1, 1962